Ok here is my problem. I am running an 18G. I just got tuned by ron. The turbo has aprox 57k miles on it. I havent checked for shaft play but I am sure there is some. On the dyno the car was awesome. on the road I have a little bit of boost issues. I can pull 20lbs of boost no problem 2nd and 3rd gears and then if I stop at a light and try to do it again I get no boost. So ron said its probably either major shaft play or my wastegate is going out. Well my boost comes on a bit late so there has to be some shaft play. Well tonight I was doing a ripper and had full boost all the way through 3rd. I slowed down to turn and I punched it in 2nd, no boost. I then accelerated with no turbo, and punched it in 3rd, still no boost. I stopped at the intersection and I hear a click sound. I take off from the stoplight and I have full boost again. Whats going on? Is my Wastegate getting stuck open? Is my turbo shaft binding against the compresser? I am going to pull my downpipe tomorrow but was hoping for some insight tonight. THanks FP18g GM BCS 20lbs of boost
sorry, this doesn't help but I got a almost new 18G for your replacement if you want. 3-4k miles on it w/zero shaft play.
sounds to me like a bcs issue, but that's just an internet guess. I'd first check that, make sure all hoses are connected tight and have no holes in them. Also check the wiring for it. When you said no boost, do you get wastegate pressure or absolute zero when accelerating?
I get absoultly zero boost. What should I be looking at on the BCS? EDIT: I checked the BCS. All the LInes are hooked up correctly. LIke I said it didnt happen on the dyno. Just when I am driving down the road.
Sounds like the waste gate is getting stuck. What I would do is remove the turbo heat shield. Make the car boost hard then pull over to see if the gate arm is stuck open.
Shinenitelite had the a problem like that. His waste gate arm would fall off of the flap. Then the flap would just sit open.
The actuator rod goes to a pivot arm. The arm is held on with a c-clip. Shannon's C clip was missing. So the wastegate door could just swing open on its own.
my actuator arm was actually hanging up on the shield. I filed the hole a little larger and it works great now
Ok I pulled the downpipe. The heatshield looked crooked so I didnt put that back on. I checked for shaft play and I didnt have any. Zero shaft play. Pretty cool for 57k miles on it. LOL. The arm was stiff as hell to move, feels a bit sticky in the actuator. But whatever. Reinstalled the downpipe and Now i have boost. It holds boost now. it does though have a couple psi of oscillation but its holding. The oscillation could be from here in fargo today its only 55 degrees so it could be spiking a bit. But it holds boost in all gears and so it seems to be fixed. I also adjusted the position of my BCS too, since it was angled a little wierd to put less tension on the vacuum lines. So we will see if it acts up down the road. O and 20lbs of boost is fun. I am going to need new brake pads soon. LOL
lol, I bet the arm was rubbing on the shield. Were there any signs of wear on the opening in the shield?
no signs of wear. The shield is modded (cut) bigger to fit the bigger turbo but I didnt see any wear marks. So I dunno
